As is traditional for Basketball Prospectus playoff previews, you will find advanced statistics for both teams from the regular season and the playoffs sprinkled throughout this breakdown of the NBA Finals. However, it is worth asking the question of whether what these teams did during the regular season matters anymore.

With their 50 wins, the Boston Celtics have joined the 2003 New Jersey Nets (49) and 2007 Cleveland Cavaliers (50) as the three weakest regular-season teams to reach the NBA Finals in the past decade. While their predecessors simply got hot at the right time to win weak conferences, the Celtics have played championship-caliber basketball over the last month and a half, knocking off first the 61-win Cavaliers and then the 59-win Orlando Magic without the benefit of home-court advantage.

ABC's trio of Mike Breen, Mark Jackson and Jeff Van Gundy, which worked the Eastern Conference Finals and will call the NBA Finals, has made repeated references to Boston getting healthy. I'm not sure that's quite accurate. The Celtics had their starting lineup intact for 20 of their last 25 regular-season games, starting when Paul Pierce returned from a thumb injury at the beginning of March. In that span, Kendrick Perkins missed three games and Kevin Garnett sat out one, yet Boston hardly finished the schedule strong, going 14-11 overall and 11-9 in the 20 games all five players started. Included in that stretch were three home losses to teams that missed the playoffs (Houston, Memphis and Washington) and a road loss to the New York Knicks.

The better explanation seems to be that the aging Celtics were saving something for the playoffs. An apt comparison has been made with Bill Russell's last team, the 1968-69 Boston squad that finished fourth in the Eastern Division with 48 wins before knocking off three higher-seeded teams en route to the championship in a last burst of glory.

While the Los Angeles Lakers merely held serve by winning the Western Conference as its top seed for the third consecutive season, the Lakers too have changed their stripes during the postseason. A middling offensive team that won primarily with defense during the regular season, the Lakers have rivaled the Phoenix Suns for scoring prowess during the postseason while struggling at the other end of the floor. The fact that the regular season has proven relatively unimportant to date in the postseason makes this Finals matchup a bit more challenging to forecast.

The Lakers' improvement on offense in the playoffs can be tied almost exclusively to shooting, and specifically two-point percentage. Los Angeles is shooting the ball better from three-point range, but the difference (.341 in the regular season vs. .348 in the playoffs) is minimal. The Lakers' two-point accuracy has taken a much larger jump from 49.2 percent during the regular season, precisely league average, to 52.3 percent in the postseason--best of any team. The change can't really be attributed to the opposition, since all three of the Lakers' foes (Oklahoma City, Phoenix and Utah) were considerably above-average in terms of defending inside the arc.

Can Bryant keep it up? He repeatedly made improbable contested shots in the Western Conference Finals, and while that was a testament to Bryant's individual brilliance, it's also not exactly a recipe for sustained success.

Outside of the open looks he got on the weak side against an overloaded zone in the first half of Game Four, it's hard to fault Phoenix for its defense on Bryant, who had to work hard for his points. Still, the quality of the opposing defense goes way up now that the Lakers are facing the Celtics and defensive mastermind Tom Thibodeau. Boston has historically used Ray Allen to defend Bryant, with plenty of assistance from the Celtics' excellent help defense and defensive specialist Tony Allen off the bench. That strategy was successful in the 2008 NBA Finals, and in the lone game Bryant played against the Celtics this season he scored just 19 points on 8-of-20 shooting.

Gasol is also facing his toughest defensive matchup of the postseason in Kevin Garnett. After he shut down Antawn Jamison and Rashard Lewis in consecutive series, nobody is talking about Garnett looking like he's dragging his right leg around. Garnett's improved mobility might be the biggest reason that a Boston offense that slipped slightly down the stretch of the regular season has returned to 2007-08 form, holding three playoff opponents thus far an average of 9.8 points per 100 possessions below their regular-season Offensive Ratings. (By contrast, the Celtics were 3.8 points better than average in the regular season.)

The matchup is more favorable for Gasol when the Lakers go small and move him to center, matching him up with Kendrick Perkins and Rasheed Wallace. As impressive as Perkins was defensively against Dwight Howard, he relies more on his strength than his quickness and has more difficulty against players like Gasol who can face up and either shoot 8-10 footers or beat him off the dribble.

At the same time, the most consistently successful Laker scorer in the two head-to-head meetings was actually center Andrew Bynum, who scored 33 points in the two games and grabbed a combined eight offensive rebounds. Bynum's action figures to continue to be limited by a small tear in his right lateral meniscus. On Monday, Bynum had his knee drained of fluid, and doctors removed nearly twice the amount taken from Bryant's right knee prior to the Western Conference Finals.

Ultimately, the Boston defense will force the Lakers to beat them with their last offensive options. That means Artest and Fisher must make shots from the perimeter. Fisher has had a playoff resurgence on the order of what we've seen from the Celtics as a whole, improving his True Shooting Percentage from .499 to .589 and canning open threes as well as long twos. Artest's postseason has been more up and down, and he shot 2-for-9 from beyond the arc against Boston during the regular season. He may not be finished playing either hero or goat just yet.

The Celtics had the lowest regular-season Offensive Rating of any team the Lakers will face in these playoffs, and while those results too have been called into question by the postseason, the difference has not been nearly as large as at the other end of the court. After accounting for the fact that the Celtics have faced three top-10 defenses in a row, their offense has operated more efficiently in the playoffs, but not dramatically so.

That said, Boston does force opposing defenses into some difficult decisions. This was apparent both in the series with Cleveland (when Mike Brown repeatedly moved around Mo Williams on defense, trying to find where he would cause the least damage) and in the Eastern Conference Finals (when Matt Barnes and Vince Carter flip-flopped matchups midway through the series).

The Lakers have their own answer, of course, that being using Bryant to defend Rajon Rondo in free safety mode, daring Rondo to become a jump shooter. Though the Celtics ultimately worked around it, that strategy was a success during the 2008 NBA Finals. Rondo is a much better player now than he was then, however. In the lone game Bryant played against Boston this season, Rondo did plenty of damage, scoring 21 points on 9-of-16 shooting. According to Hoopdata.com, Rondo shot just 1-of-5 on long jumpers in that game but was able to work his way to the basket. Watching clips on Synergy Sports, Rondo got those baskets primarily by being aggressive in transition and by beating slower defenders when Bryant helped and got caught elsewhere.

The Lakers can feel comfortable about putting Artest on Paul Pierce. Artest is one of the few defenders in the league with the combination of physical skills needed to contain Pierce, who had two quiet games in the regular season. He totaled 26 points on 8-of-20 shooting. Doc Rivers might do well to get Pierce in the game when Artest is resting, which would likely force Bryant to defend Pierce.

Cross-matching Bryant on Rondo means Fisher defends Ray Allen. The small but tough Fisher gets through screens well, which means the Lakers probably won't have to offer the same help the Magic did when Allen came off of curls. When Fisher defended Allen in the regular season, he struggled and missed all six of his three-pointers in the midst of a dreadful slump. However, Allen had a huge 2008 NBA Finals, knocking down 22 three-pointers in six games. He also poured in 24 points in the other meeting between the teams.

Up front, the Lakers should be able to defend Garnett and Perkins with either their starting lineup of Bynum and Gasol or the finishing duo of Gasol and Lamar Odom. Gasol's versatility allows him to handle either of the matchups, and Odom is physically a good match for Garnett, who had two quiet games against the Lakers in the regular season (23 combined points on 9-of-15 shooting).

As mentioned in the introduction, the Lakers haven't defended well in the playoffs. They've held their opponents an average of just 0.7 points per 100 possessions below their regular-season Offensive Ratings. The Lakers' Defensive Rating was an impressive 4.0 points better than average during the season. The biggest culprit has been pick-and-roll defense, which doesn't figure to matter much during this series. Los Angeles will have Bryant defending on the ball, and he plays far enough off Rondo that coverage when Boston does go to the pick-and-roll will be very different. Bryant may simply go under the screens if he is able to cut off Rondo on the drive. That said, the Lakers' rotations have slipped a bit before improving in the last two games of the Western Conference Finals. It remains to be seen whether that will carry over to this series.

PREDICTION

If there is one thing I've learned in this postseason, it is this: Pick against the Boston Celtics at your own peril. Before the upset over Cleveland, when regular-season performance was all we had to go on, the Cavaliers were an easy pick. Like my colleague Bradford Doolittle, I agonized a bit more over the Eastern Conference Finals before ultimately going with the Orlando Magic--my pick as champion since day one--in seven games, figuring the 82-game sample was more meaningful than the handful of great games the Celtics had played against the Cavaliers.

By now, I'm convinced Boston is legitimate and that we didn't see the true Celtics team during the regular season (at least the last four months of it). The question then becomes whether that is enough to beat a Lakers team that is playing some pretty fair basketball itself and holds home-court advantage. I think we've got a good chance of seeing the classic NBA Finals we anticipated when these two teams met two years ago and Boston won going away, which would be nice given how forgettable most recent Finals series have been.

Still, I'm picking the Lakers to win it. I like the matchups for them at the defensive end of the floor. If they can hold Rondo in check, Boston may have a difficult time consistently scoring. The Celtics will cause their own issues with their defense, but even though they were less impressive in the regular season, I think the Lakers have better-rounded talent to beat the Boston defense than Cleveland and Orlando, who were ultimately forced to rely on flawed options.

There is also, I must admit, a tiny bit of doubt about how long the Celtics can keep this up. They're coming off two difficult series and are playing Rondo 41 minutes a night and Allen and Pierce 38 apiece during the postseason. The Lakers aren't much more reliant on their bench, but the only player for whom fatigue should be any kind of an issue is Bryant. If this series goes the distance, that could work to the Lakers' favor.